Forensics capability is becoming increasingly important for the enterprise/network environment. Therefore, businesses need to find an optimised forensics solution that suits the high level business/forensics requirements. However, most businesses are still staying with the conventional method of digital investigation, which means using forensics tools to retrieve evidential data from the target system. Many businesses lack a comprehensive model to help understand the forensics requirements on different levels. Also, businesses lack a method to integrate and manage forensics knowledge into daily operation. In this research, a forensics overlay is being developed on an existing business framework – SABSA model. The overlay helps different business roles to understand and apply forensics knowledge into their daily tasks. With help of the overlay, businesses are able to reduce the overreliance on the third party forensics tools through developing their own forensically sound applications. To test the theory of forensically sound application development, and evaluate the usability of the overlay, a forensically sound email client is designed and developed accordingly.